That's No Dog (But He's Definitely Mine)
by Kalira69
Summary: Derek's been hurt (again) and Stiles just wants to keep him safe until he heals. Really. Two problems, though: one, Stiles has to get Derek past his dad first, and two, uh, Derek might actually be his soulmate? No one was prepared for this. (Soulmate AU.)


". . .you're home."

Stiles froze, turning to look at his dad. "Hi Dad! Yeah, of course I am! You said midnight, and here it is . . . eleven forty-two." he said with a grin.

"Yes, I _did_ say midnight." his dad said, giving him a suspicious look. "I'm surprised to see you."

"Did you think I would wait until the last moment?" Stiles asked, putting his hand over his heart. "Am I not ever the obedient son?"

"Never." his dad said dryly. "I don't- And what is _that_?" he demanded, taking half a step back and reaching for his hip where he would normally have his gun holstered.

Stiles winced. He was glad his dad didn't have his gun right now. He knew what his dad was seeing behind him. "Look, I-"

"Stiles, _where_ did you find- We are not keeping a dog." his dad said warningly.

"No, Dad, it's not that. . . I- I-" Stiles paused, mind spinning. "I found him!" he said hurriedly, glancing down at Derek as he slunk further in the doorway. "He's hurt, and I found him, and I brought him home to take care of him until I can take him to the vet - Scott'll take care of him, but I can't get him there until morning at least, obviously." he spun, watching his dad.

His dad looked a little exasperated and maybe disbelieving but no longer quite so worried, and he'd stopped groping at his belt, even as Derek brushed against his hip, favouring one front leg and struggling to keep his weight completely off one of his back legs. Which might still be bleeding. Stiles fretted. "You brought him home." He paused. "How did you even get him in your Jeep, he's bigger than you are."

"He's- He's a good dog." Stiles said, and Derek made a low huffing sound. "I uh, helped, but he climbed up himself."

"And you . . . _found_ him." Stiles' dad said, rubbing the bridge of his nose.

Stiles closed the door, careful to avoid trapping the end of Derek's fluffy tail. "Yes. By," he paused, because he'd been about to say where the fight had happened, and he didn't want his dad possibly thinking canine-Derek had been responsible, "the park. Almost in the street." he embellished.

"So you found a bleeding mountain of a dog on the side of the street after eleven at night, and you decided the best thing to do was stop and get out of your car?" his dad asked, and Stiles frowned. "And then to bring him home with you?"

"Well I couldn't just _leave_ him there alone, Dad!" Stiles yelped. "I'm not a _monster_! Look at him!" He crossed his arms, then uncrossed them and reached down to pat Derek's head before he thought about it. "Look, Dad, he's a good dog, he's sweet, I promise," he said, and coughed quietly as he remembered a dozen instances of Derek snarling in his face, "I'll take care of him myself, and then talk to Scott tomorrow."

"Of course you will." his dad said, but he sounded more resigned now.

"Just look at him! How could anyone have hurt such a poor puppy!" Stiles said, even as he realised that his mouth was running away with him and Derek was going to be _so_ pissed. "And I still got back before curfew." he added, lifting his chin.

"Good job." his dad said, voice dry. He approached, looking down at Derek. Derek backed up, brushing against Stiles a little more. "Oh, fine. Be _careful_." he added sharply.

"I swear he's a good dog, Dad." Stiles said again, nodding hurriedly.

"He may be, but he's also . . . hurt and bleeding." his dad said warningly. "However," he paused, "good a dog he is. . ."

"I'll be careful." Stiles promised, though he wasn't worried about Derek biting him - more that Derek wouldn't accept help even though he was possibly still bleeding and his advanced healing had obviously still not managed to deal with his injuries, which was somewhat worrying.

Ten minutes later Stiles was sorting through his first aid kit - considerably more extensive now than it had been five years ago, which was saying something given how prepared he and his dad both were about such things - while Derek sat on the edge of his bed and shifted restlessly. It wasn't fidgeting like Stiles' - Derek didn't . . . fidget - but Stiles suspected he couldn't get comfortable, his wounded limbs aching.

Stiles knelt at Derek's feet, pushing the hem of his own pyjama pants a little further up carefully, avoiding the livid wound wrapped around Derek's calf. It was still weeping, but only blood and clear fluid, so he would probably be okay.

Stiles glanced up and fumbled the gauze he was fiddling with as his eyes caught on the slanted, elaborate _**M**_ stark on Derek's skin. The spiky serifs adorning the letter made it look a little sickeningly like wolfsbane poisoning. In fact, the first time Stiles had caught a glimpse of it he had thought it was part of the poisoning that had nearly had Derek forcing him to take a saw to Derek's arm.

He swallowed, sitting back on his haunches, and ventured a look at Derek's face. His expression was closed and dark, but Stiles had known Derek for long enough now. . . He could see the uneasy uncertainty in Derek's eyes. "Derek, I-"

"I'm a good dog?" Derek asked, voice rumbling but fortunately low enough Stiles' dad wouldn't hear them even were he walking down the hall outside the closed door. Which he might be at random tonight, if he was concerned about Stiles' bringing home a 'dog' like Derek. "Really, Stiles?"

"Do you have a better explanation I should have handed him?" Stiles countered, and Derek snorted, frowning slightly, but didn't answer. The nudge of their normal balance - bantering or snarking with Derek - steadied his hands and narrowed his focus, and Stiles set to gently cleaning and bandaging Derek's wounds, ignoring his protests that it wasn't necessary. "You're all but dripping on the floor." Stiles pointed out. "It's necessary. It's been almost an hour since that fight and this barely looks like it's started to heal."

Derek leaned forwards to look, then wavered and caught himself with a hand on Stiles' shoulder. Stiles looked up at him, pausing midway through pressing the tape down over the gauze. "Uh. I- Sorry." Derek said, flushing a dull red just over his cheekbones.

He was looking at Stiles' chest, where the wendigo had nearly shredded his ribcage, but, thanks to Derek, had only ripped the front of his shirt. Stiles licked his lips, then stifled a laugh and rubbed his thumb down the edge of the tape on the gauze.

He brushed Derek's hand aside, but only to join him on the bed. He glanced down at himself, then unbuttoned the long-sleeve shirt that had fortunately escaped the wendigo's claws - otherwise he would have had some trouble hiding his torn shirt from his dad. His hoodie, his usual go-to for covering up such problems, had been soaked in blood and black wolfsbane pus two days before.

He shrugged it off, along with the shredded remains of his tee shirt, revealing again the slanted, thick lines of the _**D**_ over his heart. Derek lifted his hand, then hesitated. Stiles turned to face Derek and crossed his legs, cocking his head to one side.

"Uh. . . Stiles?" Derek asked, and Stiles hummed, tapping his finger on the intricate _**M**_. He realised his boundaries might have been somewhat demolished by all the times he'd had to patch Derek up before. And he hadn't ever before had any thought that Derek's _**M**_ was for _him_. "What . . . _is_ your name?"

"Stiles." Stiles said, but grinned. "Mieczyslaw." he offered. Derek's eyes widened. "I, er, suggest you stick with Stiles."

"Me- Mey-" Derek paused, frowning, and Stiles stifled a smile. Derek put a hand on his chest over the Mark, which pulsed with the touch in counterpoint to his heartbeat. He sighed with pleasure. "Mieczyslaw." Derek said, almost-right.

Stiles' brows rose. "You'll erase my mystique if you do call me that, but I'm impressed."

Derek grinned. "Couldn't do that." he said with a laugh, and dropped his hand. Stiles caught it, and Derek jumped, then winced as he braced a foot on the floor. His injured leg wasn't quite ready to take his weight - thus part of why Derek had come home with him in full wolf form. Four legs gave a better balance for the pain, even with the additional injury to his left arm. "Sorry." he said again, settling down. "And this. . ." he put a hand over his chest, over Stiles' initial.

"Would you really have guessed even if you knew my name?" he asked, raising his eyebrows. "I. . ." he glanced at his own Mark.

Derek looked troubled when Stiles looked up at him again. "No, that's not. . . I've- I'm not the best. . ." he trailed off.

Stiles narrowed his eyes. He wouldn't say _that's what this means, you're the best for me_ because Stiles knew - better than most - that soulmates were not a guarantee. But. . . "Don't make a choice for me." he said softly. "And don't be afraid _of_ me, either."

"I'm not. Exactly. I. . . I trust you." Derek said, and Stiles swallowed.

"That's- Good." Stiles said thickly. "You too, Derek." he said gently. "That's . . . a start."

Derek looked a little easier now, and Stiles sighed, smiling slightly. "You need to rest." he continued, resting a hand over one livid bruise on Derek's arm. "You'll be safe here. We can figure out," he caressed the _**M**_ lightly, "later."

Derek nodded, then pushed himself off the bed carefully, groaning under his breath.

"You. . ."

"I should probably change back." Derek said, looking sideways at Stiles. "Your dad?"

Stiles glanced at the door. "Not a bad idea." he admitted. "I don't think you'll fit on the bed, though."

Derek startled, then let out a low bark of laughter. "The floor will be fine. Thank you. Really." he added.

"Thank you." Stiles rose, hesitated, and lightly kissed Derek's cheek. "You saved my life tonight, too. Again." He lowered his voice. "I'm not sorry. Only surprised."

Derek paused, opening his mouth and then closing it, and then finally shifted forms without speaking again. He leaned his head against Stiles' hip, though, and when Stiles automatically moved to stroke him, didn't pull back but pushed into the gentle touch.

John paused at the top of the stairs, then turned back towards his son's room. He carefully cracked the door open and peeked inside. Stiles was sacked out, sprawled over his bed - most of the coverlet was no longer on top of him - with one foot jammed against the wall under the window.

The mountain of dog - John had his doubts that it was _actually_ a dog, it looked a little too . . . predatory not to be something wild - was lying on the floor right up against the bed. There were thick pads of gauze wrapped around two of its legs. And-

John frowned. One of Stiles' hands was dangling off the bed, and the dog's head was tucked against it, one ear folded down under Stiles' wrist. Peaceful enough, for an injured possibly-feral animal.

And clearly taken enough with Stiles to not only allow him bind its wounds but then to sleep almost at his feet.

"We are not keeping a dog." John said to himself as he closed Stiles' bedroom door, but he was no longer quite sure how well it was going to go. They didn't _need_ a dog, and it would complicate things for them to try and keep it. But he was well aware that if Stiles really _wanted_ to keep it, getting out of it would be difficult.

The dog was gone when he came home for lunch with Stiles, though, and Stiles seemed happy enough, though distracted. Stiles being distracted was nothing particularly new, however, and John wasn't concerned. He asked, and Stiles assured him with a smile that Scott had helped out and the dog would recover fully with no trouble.

John nodded and let it drop in favour of asking about the essays Stiles had been working on for his college applications.

The dog wasn't mentioned again - though for a few days John was anticipating hearing about its recovery, either from Stiles or Scott - and eventually he mostly forgot about it.

So when he stepped out of his car almost two months later to see the dog lying on his porch, he was more than a little surprised. It rose and paced out of John's way as he approached, and he frowned slightly, pulling his keys out of his pocket.

"Stiles?" he called as he entered. The dog lay down on the porch again rather than trying to come in after John. There was no answer, and the house was quiet. He closed the door.

The dog remained on the porch until Stiles came home a few hours later, but it _did_ follow him inside. John went to meet them and raised his eyebrows. "The dog appears to be back." he pointed out.

". . .yes." Stiles said, looking down. The dog perked its ears and looked back at him. "Dad, can we go . . . sit down?" He nudged John into the living room. He refused to sit down, but Stiles didn't push it, backing off again quickly.

"Um." Stiles said, and the lack of words made John very nervous. "Dad. This is. . . I figured out who my soulmate is." he said all in a rush - fast enough that John barely followed the words even with his practise. He had to focus enough it took him a moment to realise that Stiles was gesturing _at the dog_.

The dog - half-hidden behind a chair beside Stiles - ducked its head, one paw dragging over its face. "Stiles-" John choked as then Derek Hale rose from behind the chair. Without a shirt. And with an ornate, spiky _**M**_ now visible over his heart. " _What?_ "

Vaguely, beyond his utter shock at the shift from the dog to Derek, John remembered the Mark on his son's chest, of course he did - the thick, heavy _**D**_ that- _Derek_.

"So, Dad. . . There might be a few things we should talk about?" Stiles said with a wince. "I may have . . . kept some things back. Over the years. About Beacon Hills. And. . ." he trailed off. And a lot of things, John guessed.

"Did it occur to you that you should maybe have started with something smaller than _all of it_?" Derek said and Stiles shot him a blank look. John sat down, rubbing his face.

"All of it?" John asked, then squeezed his eyes closed for a moment, head spinning. "Start with how your soulmate is not a dog." he suggested, because that was the most immediately concerning.

"Start with pants." Stiles hissed at Derek, and a moment later the dog trotted out of the living room and up the stairs. "I'm sorry, Dad." he said earnestly, and John nodded. "I have a lot to catch you up on." he continued, and John nodded again, jaw clenching. "Are you mad about Derek?" he asked, looking genuinely fretful, his eyes wide and nervous.

It was a familiar expression, and the fidgeting as his fingers tapped and tangled together was the same fidgeting John had been watching for years, and his son . . . was good at making even terrible choices with amazing amounts of reasoning. "I'm not mad about Derek." he said. "He's your soulmate," he didn't question, "I can't be mad about that. I am reserving judgement on _everything else_. Explain. All of it."

* * *

This was written for the prompt 'Obedient' (the friend whose fault this is laughed hysterically about that prompt coming up for this pairing) for a multi-fandom set of soulmate AU stories. I somewhat lost control of it partway through, and it became longer and more complex than first plotted to be.


End file.
